Locking devices for support of tools such as plugs in a tubular string have been used in the past. These designs use a recess profile in the string as the location for the engagement of the lock device that supports the tool such as a plug. Typically the string has a no go shoulder so that when the assembly is introduced into the string and hits a travel limit there are an assembly of dogs that are selectively extendable through windows in the housing. These dogs are then extended radially by a sleeve within the tool that has an exterior ramp that engages the dogs. As the sleeve advances the dogs are cammed out and the sleeve has a larger diameter behind the camming ramp that then serves to keep the dogs extended into a profile in a landing collar that is part of the tubular string. The seal of a plug that is installed in this manner lands in a seal bore and is subjected to tensile or compressive stresses depending on the direction of differential pressure. One of the issues with this design in tensile loading with pressure differential coming from above is that the stress is transmitted through the window structure and the thin segments of the housing that defines the region between the windows so that the stress on the housing can get to the dogs that are extended into the recess of the landing nipple in the tubing string. Some examples of this design are U.S. Pat. Nos. 4,510,995 and 4,583,591.
Another design that can anchor to a surrounding structure is a collet system where the collets are a thick wall segment in the middle of strips made from machined slots in a tubular housing to lend flexibility to the collets for running in and setting when aligned with a groove of a tool downhole. This collet design is generally used in light duty applications such as shifting a sleeve as opposed to supporting an assembly subjected to high stresses from differential pressure such as a plug in a tubular string. These types of tools have generally been run inside other tools to operate an internal component in an existing downhole tool followed by removal when that task is accomplished.
Yet another type of intelligent collet is described in U.S. Pat. No. 6,464,006 that allows selecting landing or bypassing a support platform to properly position a multi-position crossover tool in a gravel packing context.
The present invention seeks to use the flexible finger style collet as an anchor device to a tubular string when supporting a tool that will undergo large loads such as 30,000 pounds of force or more. In adapting such as design for high load application the present invention includes features that allow the ability of large compressive loads to essentially bypass the weaker supporting finger structure so that load goes to the collet in the surrounding groove directly through the provision of an external sleeve that doubles in duty as the locating sleeve for the anchor assembly. The fingers are provided with an exterior inward taper so that in the set condition they are axially aligned with the surrounding tubular access rather than being bent outwardly when in the set position. Such an initial orientation also helps to retract the collets when support is removed for retrieval because of their tendency to retract to pull the collet out of the surrounding profile recess when support is removed. These and other features of the present invention will be more apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims.